We note that there are other approaches to overcome the low resource problem, such as unsupervised learning [1]}, [2]}, , as well as transfer learning, which we describe in the following section. These approaches are not mutually exclusive, therefore we can combine them. For example, transfer learning—pre-training language representation models on unlabelled data, and then fine-tuning on target labelled data—has become a standard practice in NLP. Methods belonging to other approaches can be combined with transfer learning, such as using off-the-shelf pre-trained models as the baseline model.
